a 2000 W electrical fire is used for 10 hours , what is the cost at 8p per kWh

energy = power * time

cost = number of kWh * cost per kWh

2 kW * 10 = 20 kWh

20*8 = 160p

if electrical energy costs 9p per unit , calculate the cost of leaving a 3 kW fire switched on for 12 hours

energy = power * time

cost = cost per kWh * number of kWh

3 * 12 = 36 kWh

36 * 9 = 324p

if electrical energy costs 9p per unit , calculate the cost of leaving a 120 W T.V. switeched on for 8 hours

energy = power * time

cost = cost per kWh * number of kWh

0.12 * 8 = 0.96 kWh

0.96 * 9 = 8.64p

an electric lamp is marked 100 W . find the cost of using it for 6 hours at 8p per unit

energy = power * time

cost = number of kWh * cost per kWh

0.1*6 = 0.6 kWh

0.6 * 8 = 4.8p

a 3 kW fire is switched on for 15 minutes . calculate the cost if electrical energy is 9p per unit

energy = power * time

cost = number of kWh * cost per kWh

3*15/60 = 0.75 kWh

0.75 * 9 = 6.75p

the diagram below shows an electricity/energy meter a) how much electricity has been used
b) the electricity costs 9p per unit . whats is the cost of using this quantity of electricity
c) 2047 units are used in the next billing period . What is the new reading on the meter